Decoder/encoder for NMEA-0183 message types.

npm install -S @gnss/nmea

let buffer: string = ...; // String containing NMEA sentence
let message: NmeaMessage = NmeaTransport.decode(buffer);

let message = ...; // Message to be encoded
let buffer: string = NmeaTransport.encode(message);

Messages can be manually constructed using NmeaMessage???.construct({}), which requires all message properties to be provided.

NmeaMessageGga.construct({
    talker: NmeaTalker.NAV_SYSTEM_GNSS,
    time: new Date(0, 0, 0, 1, 2, 3, 0),
    latitude: 66.66,
    longitude: 33.33,
    quality: NmeaFixQuality.SIMULATOR,
    numberSatellites: 10,
    hdop: 2.5,
    altitude: 180.00,
    geoidalSeparation: 90.00,
    differentialAge: 5,
    differentialStationId: 'differentialStationId',
})

Transform streams to convert from NmeaMessages to sentence strings and vice-versa.

let input: stream.Readable = ...;
let output: stream.Writable = ...;
input                                      // Stream of sentence strings
    .pipe(new NmeaDecodeTransformStream()) // Stream of NmeaMessage objects
    .pipe(new NmeaEncodeTransformStream()) // Stream of (identical) sentence strings
    .pipe(output);

NmeaDecodeTransformStream can optionally synchronize with the data stream e.g. if it starts receiving data from the middle of a message.

• DTM (NmeaMessageDtm)
• GBS (NmeaMessageGbs)
• GGA (NmeaMessageGga)
• GLL (NmeaMessageGll)
• GNS (NmeaMessageGns)
• GRS (NmeaMessageGrs)
• GSA (NmeaMessageGsa)
• GST (NmeaMessageGst)
• GSV (NmeaMessageGsv)
• RMC (NmeaMessageRmc)
• THS (NmeaMessageThs)
• TXT (NmeaMessageTxt)
• VHW (NmeaMessageVhw)
• VLW (NmeaMessageVlw)
• VPW (NmeaMessageVpw)
• VTG (NmeaMessageVtg)
• ZDA (NmeaMessageZda)

npm test

GPLv3

Contributions of new sentence types, bug fixes and general improvements via pull requests are welcome. Please ensure that code style matches that of the existing files.